3英文翻譯(珩磨)

1、Fundamentals of Mechanical DesignMechanical design means the design of things and systems of amechanical naturemachines, products, structures, devices,andinstruments. For the most part mechanical design utilizes mathematics,thematerials sciences, and the engineering-mechanics sciences.The total desi

2、gn process is of interest to us. Howdoes it begin?Doesthe engineer simply sit down at his desk with a blank sheet of paper? And,as he jots down some ideas, what happens next? What factors influence orcontrol the decisions which have to be made? Finally, then, how does thisdesign process end?Sometime

3、s, but not always, design begins when an engineer recognizesa need and decides to do something about it. Recognition of the need andphrasing it in so many words often constitute a highly creative act becausethe need may be only a vague discontent, a feeling of uneasiness, or a sensingthat something

4、is not right.The need is usually not evident at all. For example, the need to dosomething about a food-packaging machine may be indicated by thenoise level,by the variation in package weight, and by slight but perceptiblevariationsin the quality of the packaging or wrap.There is a distinct differenc

5、e between the statement of the need andthe identification of the problem which follows this statement.The problemis more specific. If the end is for cleaner air, the problem might be thatof reducing the dust discharge from power-plant stacks, or reducing thequantity of irritants from automotive exha

6、usts.Definition of the problem must include all the specifications for the thingthat is to be designed. The specifications are the input and outputquantities, the characteristics and dimensions of the space the thing mustoccupy and all the limitations on these quantities. In this case we mustspecify

7、 the inputs and outputs of the box together with theircharacteristics and limitations. The specifications define the cost, thenumber to be manufactured, the expected life, the range, the operatingtemperature, and t he reliability.There are many implied specifications which result either from thedesi

8、gner ' s particular environment or from the nature of the problem itself.The manufacturing processes which are available, together with thefacilities of a certain plant, constitute restrictions on a designerfreedom, and hence are a part of the implied specifications. A small plant,for instance,

9、may not own cold-working machinery. Knowing this,the designerselects other metal-processing methods which can be performedin the plant.The labor skills available and the competitive situation also constituteimplied specifications.After the problem has been defined and a set of written and impliedspe

10、cifications has been obtained, the next step in design isthe synthesisof an optimum solution. Now synthesis cannot take placewithout bothanalysis and optimization because the system under design must be analyzedto determine whether the performance complies with the specifications.The design is an it

11、erative process in which we proceed through several steps,evaluate the results, and then return to an earlier phase of the procedure.Thus we may synthesize several components of a system, analyze and optimizethem, and return to synthesis to see what effect this has on the remainingparts of the syste

12、m. Both analysis and optimization require that weconstruct or devise abstract of the system which will admit some form ofmathematical analysis. We call these models mathematical models. Increating them it is our hope that we can find one which will simulate thephysical system very well.Evaluation is

13、 a significant phase of the total design process.Evaluation is the final proof of a successful design, which usually involvesthe testing of a prototype in the laboratory. Here we wish to discover ifthe design really satisfies the need or needs. Is it reliable? Will itcompete successfully with simila

14、r products? Is iteconomical to manufactureand to use? Is it easily maintained and abjusted?Can a profitbe made fromits sale or use?Communicating the design to others if the final,vital step in the designprocess. Undoubtedly many great designs, inventions, and creative workshave been lost to mankind

15、simply because the originators were unable orunwilling to explain their accomplishments to others. Presentation is aselling job. The engineer, when presenting a new solution to administrative,management, or supervisory persons, is attempting to sell or to prove tothem that this solution is a better

16、one. Unless this can be done successfully,the time and effort spent on obtaining the solution have been largely wasted.Basically, there are only t here means of communication available to us.These are the written, the oral, and the graphical forms. Therefore thesuccessful engineer will be technicall

17、y competent and versatile in all threeforms of communication. A technically competent person who lacks abilityin any one of these forms is severely handicapped. If ability in all threeforms is lacking, on one will ever know how competent that person is!The competent engineer should not be afraid of

18、the possibility of not succeeding in a presentation. In fact, occasional failure should be expected because failure or criticism seems to accompany every really creative idea.There is a great deal to be learned from a failure, and the greatest gains are obtained by those willing to risk defeat. In t

19、he final analysis, the real failure would lie in deciding not to make the presentation at all.Machine design is the application of science and technology to devise newis a vastshape andor improved products for the purpose of satisfyinghuman needs. It field of engineering technology which not only co

20、ncerns itself with the original conception of the product in terms of terms of its size, construction details, but also considers the various factors involved inthe manufacture, marketing and use of the product.People who perform the various functionsof machine design aretypicallyMachine design is b

21、asically ato being innovative, a designcalled designers, or design engineers.creative activity. However, in addition engineer must also have a soild background in the areas of mechanical drawing, kinematics, dynamics, materials engineering, strength of materials and manufacturing processes.As stated

22、 previously, the purpose of machine design is to produce a product which will serve a need for man. Inventions, discoveries and scientific knowledge by themselves do not necessarily benefit people; only if they are incorporated into a designed product will a benefit be derived.It should be recognize

23、d, therefore, that a human need must be identified before a particular product is designed.Good designs require trying new ideas and being willing to take a certain amount of risk, knowing that if the new idea does not work the existing method can be reinstated. Thus a designer must have patience, s

24、ince there is no assurance of success for the time and effort expended. Creating a completely new design generally requires that many old and well-established methods be thrust aside. This is not easy since many people cling to familiar ideas, techniques and attitudes. A design engineer should const

25、antly search for ways to improve an existing product and must decide what old, proven concepts should be used and what mew, untried ideas should be incorporated.Newdesigns generally have“bugs” or unforeseen problems which must be worked out before the superior characteristics of the new designs can

26、be enjoyed. Thus there is a chance for a superior product, but only at higher risk. It should be emphasized that, if a design does not warrant radical new methods, such methods should not be applied merely for the sake of change.During the beginning stages of design, creativity should be allowed to

27、flourish without a great number of constraints. Even though manyimpractical ideas may arise, it is usually easy to eliminate them in the early stages of design before firm details are required by manufacturing. In this way, innovative ideas are not inhibited. Quite often, more than one design is dev

28、eloped, up to the point where they can be compared against each other.It is entirely possible that the design which is ultimately accepted will use ideas existing in one of the rejected designs that did not show as much overall promise.Psychologists frequently talk about trying to fit people to the

29、machines they operate. It is essentially the responsibility of the design engineer to strive to fit machines to people. This is not an easy task, since there is really no average person for which certain operating dimensions and procedures are optimum.Another important point which should be recogniz

30、ed is that a design engineer must be able to communicate ideas to other people if they are to be incorporated. Initially, the designer must communicate a preliminary design to get management approval. This is usually done by verbal discussions in conjunction with drawing layouts and written material

31、. To communicate effectively, the following questions must be answered:Does the design really serve a human need?Will it be competitive with existing products of rival companies?Is it economical to produce?Can it be readily maintained?Will it sell and make a profit?Only time will provide the true an

32、swers to the preceding questions, but the product should be designed, manufactured and marketed only with initial affirmative answers. The design engineer also must communicate the finalized design to manufacturing through the use of detail and assembly drawings.Quite often, a problem will occur dur

33、ing the manufacturing cycle. It may be that a change is required in the dimensioning or telegramming of a part so that is can be more readily produced. This falls in the category of engineering changes which must be approved by the design engineer so that the product function will not be adversely a

34、ffected. In other cases, a deficiency in the design may appear during assembly or testing just prior to shipping. These realities simply bear out the fact that design is a living process. There is always a better way to do if and the designer should constantly strive towards finding that better way.

35、機械設計基礎機械設計方法的設計和系統(tǒng)的機械性的東西 ,機器、產品結構、 設備、工具. 在 大多數(shù)情況下使用數(shù)學機械設計、材料科學與工程機械科學 . 總設計過程關心我們 . 如何開始 ? 請問工程師是在辦公桌坐下空白紙 ? 并找到了 他的一些想法 , 未來會出現(xiàn)什么情況 ? 什么因素影響或控制而被迫作出的決定 . 最 后, 則是如何設計這個過程結束 .有時 ,但并不總是 ,設計工程師開始時 ,承認有必要做決定的時候了 . 必須承認 , 它在重復這么多話往往是富有創(chuàng)造性的行為 , 因為可能需要在模糊的不滿 ,感到不 安 , 或感應到一些不正確的 .通常需要在所有并不明顯 . 舉例來說 , 有必要做

36、一些食品包裝機可顯示的音量,不同的方案重量 ,并略有差異 , 但明顯的質量和包裝容器 .有明顯差別 , 需要說明的問題 , 確定了以下這一聲明 . 更具體的問題 . 如果最 后是清新空氣 , 這個問題可能是從減少粉塵排放發(fā)電廠焚燒或減少汽車廢氣量從手 腕.問題的定義必須包括所有規(guī)格的事 , 是設計 . 規(guī)格的投入和產出的數(shù)量、規(guī)模 和特色的東西要占據空間的限制 , 所有這些數(shù)量 . 在這種情況下 , 我們必須明確投 入和產出的盒子連同其特點和局限性 . 規(guī)格確定成本 , 多是生產、生活的期望、范 圍、經營溫度 t 和他的可靠性 .這意味著有許多具體的結果是設計者的特定環(huán)境還是從自身的性質問題

37、. 現(xiàn) 有的制造工藝 ,與某工廠設施 , 構成限制設計師的自由 , 因此是一種隱含的規(guī)范 . 小 廠為例 , 本身并不冷工作機制 . 知道這一點 , 設計師選擇其他金屬加工方法 , 可以在 全廠進行 . 現(xiàn)有的勞動技能和競爭力的具體情況 , 也是暗示 .在已確定的問題 , 并寫了一套規(guī)范意味著獲得 , 下一步是設計一個最佳的綜合 解決方案 . 現(xiàn)在不能進行綜合分析和優(yōu)化 , 因為制度設計分析 , 以確定是否要執(zhí)行 符合規(guī)格 .階段的程序 . 因此, 我們可以組成一個個綜合系統(tǒng) 看這對系統(tǒng)的剩余部分 . 分析和優(yōu)化的要求 種數(shù)學分析 . 我們要求這些模型的數(shù)學模型 模擬系統(tǒng)的實際很好 .評估是一

38、個重要階段 , 總的設計過程 .設計是一個反復的過程中 ,我們通過幾個步驟進行 ,評估結果 , 然后再回到早期, 分析和優(yōu)化 , 并返回綜合效應看最后證明是評價設計成功了 , 通常都是. 是 ? 這是經濟生產和使用 . 這是堅持和, 我們設計建造或抽象的系統(tǒng) , 承認某 . 他們建立的是 , 我們希望能找到一個在實驗室測試樣本 . 在這里 ,我們發(fā)現(xiàn) , 如果想真正滿足需要或者設計的需要 否可靠 ? 是否與同類產品的競爭中脫穎而出 調整容易 ? 可以從銷售利潤取得或使用 ?如果別人溝通設計最后 , 在設計過程中的重要一步 . 毫無疑問 , 許多偉大的設 計、發(fā)明、創(chuàng)作 , 已經失去了人類的原因

39、不能或不愿解釋別人的成就. 職業(yè)介紹是一個賣 . 工程師 , 當提出一個新的解決行政、 管理或監(jiān)督人員 , 試圖出售或向他們證 明這種辦法是比較好的 . 如果能夠這樣做的成功 , 所花費的時間和努力得到解決 , 有相當大的浪費 .基本上 , 只有這里 t 為我們提供的通信手段 . 這是書面、口頭、圖表和表格 . 因 此, 成功的工程師將有能力和技術技能三種傳播方式. 有技術專長的人 , 這些人沒有任何形式的能力受到很大的限制 . 如果有三種形式缺乏 , 人都知道有關這個人 ! 主管工程師不應害怕失敗的可能性 ,以說明. 事實上 ,有時不批評、 不應該是意料中 事, 因為每個真陪同創(chuàng)意 . 還有很多是從失敗的 , 最大的收獲是得到那些愿意失敗 風險 . 歸根到底 ,就在于沒有真正的決定不作報告的 . 機械設計的應用